This invention relates to surgical electrodes, and more particularly to an improvement in needled surgical electrodes to facilitate the attachment of the electrode to electrical generating or monitoring devices.
Surgical electrodes for use as heart pacer electrodes are well known in the medical profession. In general, such electrodes are constructed of a number of fine stainless steel wires twisted together to form a single flexible, multifilament electrode wire. The major portion of the wire is insulated with a polyethylene, silicone, nylon, or other non-conducting coating, with a short length of wire at either end left uninsulated. To one uninsulated end of the electrode wire there is attached by swaging or other means a fine curved needle for piercing the heart tissue to place the uninsulated end of the electrode in the myocardium. At the other end of the electrode wire is affixed a straight or Keith-type cutting needle for piercing the thoracic wall to lead the electrode to an outer point for connection with the pacemaker. Once the electrode has been properly positioned, the needles are clipped off or snapped off, as in the case of U.S. Pat. No. 4,010,756, and the uninsulated end of the electrode is ready for attachment to the pacemaker as required for stimulating or regulating the beating of the heart.
Insulated stainless steel sutures and their application as heart pacer electrode wires are described generally in U.S. Pat. Nos. 3,035,583; 3,125,095 and 3,847,156, which patents are incorporated herein by reference.
The electrodes of the prior art have disadvantages in that when the electrode has been positioned for heart stimulation, the needle on the end exterior to the body must be clipped off and the bare stainless steel wire then attached in electrical contact to the pacemaker unit, or the needle itself must be snapped off and the remaining attached shank used as an electrical jack for connection to the pacemaker unit. The steps of needle removal and wire attachment are separate, time consuming acts at a critical stage of the heart surgery. Moreover, upon repeated attachment, removal and reattachment, the ends of the stainless steel wire may fray and become difficult to work with. In the snap-off or break-away lead wire disclosed in U.S. Pat. No. 4,010,756, there is always the danger that there may be sharp edges on the electrical jack portion of the needle which might tear the surgeon's gloves and compromise the sterile field or that the pacemaker may be damaged when the shank of the needle is inserted therein.
The present invention works an improvement over the prior art by simplifying and/or refining the attachment, removal and reattachment of the electrode to the pacemaker. It is accordingly an object of the present invention to provide a surgical electrode having a needle which can be removed without cutting or breaking. It is a further object of this invention to provide a surgical electrode which is quickly and easily attached to a pacemaker after removal of the needle. It is yet a further object of this invention to provide surgical electrodes having blunt pointed electrical connecting means adapted for pacemaker electrical devices.